more power?

i have a 360 magnum crate engine, its the 300hp 375 ft lb of torque 360 magnum crate engine, bought it thru my local dodge dealership, im running hedman headers dual exhaust with an H-pipe and 24 inch glass packs, i have the dual plane edelbrock rpm air-gap intake manifold, the 600cfm edelbrock performer series carb, the mopar electronic ignition and distributer, got the napa echlin rotor and distributer cap, and a borg warner coil.
What other easy and affordable bolt ons can i do to squeeze a little more out of this engine? i was once told to pop the valvle coves off and change something in there but i forget wether it was the lifters or what? oh and somone also suggested that i run the weiand stealth dual plane intake manifold instead of the rpm air-gap, im not at all disapointed with the engine it performs very well, runs good and strong, only complaint i really have with it is that it takes forever to warm up, but i am running a carb and i do not have the manual choke hooked up yet.